diff --git a/lib/logthrsource/logthrsourcedrv.c b/lib/logthrsource/logthrsourcedrv.c
index 1920f9b1d9..6817fbd60c 100644
--- a/lib/logthrsource/logthrsourcedrv.c
+++ b/lib/logthrsource/logthrsourcedrv.c
@@ -108,8 +108,15 @@ log_threaded_source_worker_options_defaults(LogThreadedSourceWorkerOptions *opti
 
 void
 log_threaded_source_worker_options_init(LogThreadedSourceWorkerOptions *options, GlobalConfig *cfg,
-                                        const gchar *group_name)
+                                        const gchar *group_name, gint num_workers)
 {
+  if (options->super.init_window_size == -1)
+    {
+      options->super.init_window_size = 100 * num_workers;
+    }
+
+  options->super.init_window_size /= num_workers;
+
   log_source_options_init(&options->super, cfg, group_name);
   msg_format_options_init(&options->parse_options, cfg);
 }
@@ -285,7 +292,7 @@ _init_workers(LogThreadedSourceDriver *self)
 
   GlobalConfig *cfg = log_pipe_get_config(&self->super.super.super);
 
-  log_threaded_source_worker_options_init(&self->worker_options, cfg, self->super.super.group);
+  log_threaded_source_worker_options_init(&self->worker_options, cfg, self->super.super.group, self->num_workers);
 
   for (size_t i = 0; i < self->num_workers; i++)
     {
diff --git a/lib/logthrsource/logthrsourcedrv.h b/lib/logthrsource/logthrsourcedrv.h
index 7a44285e99..67baf2a446 100644
--- a/lib/logthrsource/logthrsourcedrv.h
+++ b/lib/logthrsource/logthrsourcedrv.h
@@ -84,7 +84,7 @@ struct _LogThreadedSourceDriver
 
 void log_threaded_source_worker_options_defaults(LogThreadedSourceWorkerOptions *options);
 void log_threaded_source_worker_options_init(LogThreadedSourceWorkerOptions *options, GlobalConfig *cfg,
-                                             const gchar *group_name);
+                                             const gchar *group_name, gint num_workers);
 void log_threaded_source_worker_options_destroy(LogThreadedSourceWorkerOptions *options);
 
 void log_threaded_source_driver_set_transport_name(LogThreadedSourceDriver *self, const gchar *transport_name);
diff --git a/modules/grpc/otel/otel-source.cpp b/modules/grpc/otel/otel-source.cpp
index 3658f9d466..f0b8dca06b 100644
--- a/modules/grpc/otel/otel-source.cpp
+++ b/modules/grpc/otel/otel-source.cpp
@@ -116,10 +116,13 @@ syslogng::grpc::otel::SourceDriver::init()
 
   msg_info("OpenTelemetry server accepting connections", evt_tag_int("port", port));
 
-  super->super.worker_options.super.init_window_size /= super->super.num_workers;
-
   if (fetch_limit == -1)
-    fetch_limit = super->super.worker_options.super.init_window_size;
+    {
+      if (super->super.worker_options.super.init_window_size != -1)
+        fetch_limit = super->super.worker_options.super.init_window_size / super->super.num_workers;
+      else
+        fetch_limit = 100;
+    }
 
   /*
    * syslog-ng-otlp(): the original HOST is always kept
diff --git a/news/bugfix-310.md b/news/bugfix-310.md
new file mode 100644
index 0000000000..49305bbd7c
--- /dev/null
+++ b/news/bugfix-310.md
@@ -0,0 +1 @@
+`opentelemetry()`, `axosyslog-otlp()` sources: fix crash when `workers()` is set to `> 1`